Selective expression of the p70 subunit of the interleukin-2 receptor on lymphocytes from patients with infectious mononucleosis.
The lymphocytosis manifested in infectious mononucleosis (IM) during acute phase is ascribed to a reactive expansion of CD8+ T lymphocytes caused by Epstein-Barr virus (EBV)-infected B lymphocytes. Expression of HLA-DR antigen on IM lymphocytes suggests that these T lymphocytes are somehow activated in vivo. In the present study, we analyzed the interleukin-2 (IL-2) receptor expression on lymphocytes from six patients with acute IM. Radiolabeled IL-2 binding assay revealed that IM lymphocytes from all patients examined had a considerable number of IL-2 binding sites with an intermediate affinity, although they did not express the IL-2 receptor recognized by anti-Tac antibody (p55). The number of binding sites (1,070 to 4,600 sites per cell) was larger than that of a normal, resting T lymphocyte-enriched population (650 sites per cell). Furthermore, IM lymphocytes showed marked proliferative responses to higher concentrations of IL-2, which were almost completely blocked by an anti-p70 IL-2 receptor antibody, indicating that their IL-2 receptor is a functional receptor. The results of an affinity cross-linking study seem to indicate that the IL-2 receptor expressed on IM lymphocytes is p70, the second chain of the IL-2 receptor distinct from p55. Flow cytometric analysis following immunofluorescent staining with anti-p70 IL-2 receptor antibody confirmed p70 expression on CD8+ HLA-DR+ lymphocytes. These data suggest that p70 IL-2 receptor expression is involved in the immune response triggered by EBV infection.
Kamio
M
M
First Division of Internal Medicine, Faculty of Medicine, Kyoto University, Japan.
Uchiyama
T
T
Hori
T
T
Kodaka
T
T
Ishikawa
T
T
Onishi
R
R
Uchino
H
H
Yoneda
N
N
Tatsumi
E
E
Yamaguchi
N
N
D000208:Acute Disease; D000345:Affinity Labels; D015703:Antigens, CD / Q000032:analysis; D005434:Flow Cytometry; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D007244:Infectious Mononucleosis / Q000378:metabolism*; D007376:Interleukin-2 / Q000378:metabolism; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000378:metabolism*; D046911:Macromolecular Substances; D008970:Molecular Weight; D011940:Receptor Aggregation; D015375:Receptors, Interleukin-2 / Q000378:metabolism*
D000345:Affinity Labels; D015703:Antigens, CD; D006684:HLA-DR Antigens; D007376:Interleukin-2; D046911:Macromolecular Substances; D015375:Receptors, Interleukin-2